1. Field of the Invention
The present invention is directed towards methods of culturing non-keratinocyte epithelial cells, with the methods comprising culturing non-keratinocyte epithelial cells in the presence of feeder cells and a calcium-containing medium while inhibiting the activity of Rho kinase (ROCK) in the feeder cell, the non-keratinocyte epithelial cells or both during culturing. The present invention is also directed towards methods of using these immortalized non-keratinocyte epithelial cells.
2. Background of the Invention
Vital organs like the lung, the kidney, liver, pancreas and the skin are characterized by, among other things, the presence of organ-specific differentiated epithelial cells. The differentiated epithelial cells are of course related to the specific function of each such organ. The specific functions may be as varied as, for example, gas exchange in the lung, filtration in the kidney, detoxification and conjugation in the liver, insulin production in the pancreatic islet cells or protection against a hazardous environment by the skin. Disease or degeneration of such an organ is often life threatening because degenerated or lost organ structure is often poorly replaced and because the specialized cells of one organ cannot take over the function of another organ.
Differentiated cells such as kidney epithelial cells, insulin-producing cells in the Islets of Langerhans of the pancreas, and glandular and/or hair follicle cells of the dermis are difficult to recover, if possible at all, and even more difficult to maintain once taken out of their context in the body. Indeed, differentiated epithelial cells have a very limited lifespan in culture. Generally speaking, epithelial cells, other than keratinocytes, harvested from animals can be grown in culture perhaps through only one or two passages.
To study non-keratinocyte epithelial (NKE) cells in vitro, some type of genetic manipulation such as inserting viral or cellular oncogenes, is required to allow the cells to survive more than a few passages. These genetic manipulations, however, change the cells' genetic background as well as physiology such that cells may not resemble or function like normal epithelial cells. Moreover, these genetically-modified cells would not be candidates for implantation into an intact animal.
What is needed in the art are methods of culturing NKE cells harvested from organs for extended periods of time, without having the genetically alter the cells. The present invention solves the problems associated with culturing NKE cells for extended periods of time without the need for genetic manipulation.